This group has been engaged in studying the structure, function and dynamics of the early organelles of the secretory vacuolar system. The group studies three aspects of these problems: 1) Architectural editing - a concept that has evolved out of the work of this group in explaining the cell biologic processes that underlie the ability of the cell to correctly structure newly synthesized membrane proteins and to edit out incomplete or incorrect proteins or protein complexes. One of the major mechanisms by which the cell prevents the expression on the cell surface of abnormal membrane proteins is by targeting those proteins for degradation. This group has identified a new pathway for intracellular degradation that takes place within the endoplasmic reticulum. 2) The structure and dynamics of membrane flow in the secretory pathway - this group has identified a novel drug Brefeldin A, that has unique effects on organellar structure and dynamics. Based upon the effects of this drug we have characterized new pathways of movement between the Golgi, intermediate compartments, and the endoplasmic reticulum. 3) Antigen presentation - this group has identified the endoplasmic reticulum as the major site for the presentation of endogenous antigens to major histocompatibility complex molecules.